Universal double cut die set

ABSTRACT

A tubing cutoff die having a horizontally moving scarfing blade and a vertically moving cutoff blade. The tubing being cut off is held in clamping jaws movably mounted on the lower die shoe of the die and actuated by a cam extending from the upper die shoe. The scarfing blade is also mounted for horizontal reciprocation on the lower shoe and actuated by another cam fixed to the upper shoe. The cutoff blade is mounted on the upper die shoe. The two die shoes are reciprocably connected by post and bushing arrangements. There are three of these disposed so that the centerlines are at three of the corners of a rectangle. One of the clamping jaws is mounted on a holder reciprocably mounted on the lower die shoe and the other jaw is mounted on a second holder reciprocably mounted on the first holder. The mounting for the cutoff block provides for either of two rigidly located positions, for different tubing sizes, and the scarfing blade is also adjustable.

This invention is directed to improvements in die sets and includingimprovements in arrangements for interconnecting and guiding relativelymovable parts of die sets. As described herein, in its preferredembodiment the die set is one for cutting off tubing; however, theprinciples of the invention are applicable to other types of die sets.

One feature of the invention is an arrangement for guiding the two majorrelatively movable parts or shoes of the die set for reciprocationrelative to each other. This is embodied in a set of three guide postsand three guide bushings for the posts, with the axes of the postslocated approximately at three corners of a rectangle. Thus, with anarrangement of only three guide posts, the structure is supported so asto be free from likelihood of binding resulting from transverse forcesengendered by the transverse component of motion of the ram which drivesthe die parts together. This fits the die set for use with presses ofdifferent types; specifically, those in which the ram has a component ofmotion along the axis of the tube which is being cut, and those in whichthe ram has a component of motion transverse to the tube axis.

Another feature lies in an improved structure of the clamp which holdsthe tubing during the cutting operation. The tube is clamped between twojaws, as is common. In the improved arrangement according to theinvention one of these jaws is mounted on a first slide which isreciprocably guided on one die shoe. The other jaw is mounted on asecond slide which is reciprocably mounted on the first slide. Thispromotes a simpler and lighter structure and better alignment of theclamping jaws.

A third feature is an arrangement for clamping the cutoff blade securelyand transmitting force to it positively in two settings relative to thedie shoe, with a very simple arrangement.

The principal objects of my invention are to provide improved die setsbetter adapted to the requirements of practice and to effect economiesin the manufacture of such die sets.

The nature of the invention and its advantages will be clear to thoseskilled in the art from the succeeding detailed description of thepreferred embodiment of the invention and the accompanying drawingsthereof.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of a die set embodying the invention;

FIG. 2 is a plan view of the lower die shoe and parts mounted directlyon it;

FIG. 3 is an elevation view as seen from the right hand side of FIG. 1;

FIG. 4 is an elevation view as seen from the left hand side of FIG. 1;

FIG. 5 is a vertical sectional view of the holding jaw mechanism takenon the plane indicated by the line 5--5 in FIG. 2.

FIG. 6 is an elevation view of the cutoff blade and mounting meanstherefor.

FIG. 7 is a sectional view taken on the plane indicated by the line 7--7in FIG. 6.

FIG. 8 is a sectional view taken on the plane indicated by the line 8--8in FIG. 6.

FIG. 9 is a view similar to FIG. 7 showing a different set-up of theblade mounting means.

FIG. 10 is a partial elevation view of the cutoff blade.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT

Referring first to FIG. 1, the die set 2 includes a lower die 3 and anupper die 4. The lower die parts are mounted on a lower die shoe 6 andthose of the upper die on an upper die shoe 7. These are heavy machinedmetal plates.

The lower shoe is supported by the bed of a press and the upper die shoeis reciprocated vertically by the ram of the press. The means by whichthe shoes are connected to the press may follow customary practice andtherefore will not be illustrated or described. The upper die will beconsidered as the movable die, although the lower die could be the onemoved. The upper die is supported for such reciprocation on the lowerdie by three sets of guide means 8. Each guide means comprises a tubularguide post 10 having a flange fixed to the lower shoe 6 by socket headscrews 11. A bushing 12 similarly fixed to the upper shoe 7 fits overthe post. It will be most clearly apparent from FIG. 2 that the threeguide posts 10 are located at three of four corners of a rectangle withthe axes of two of the guide posts 10 lying in a plane which makes avertical intersection with the plane of FIG. 2 whereas one of those pinsand the third have axes which lie in a plane which makes a horizontalintercept with the plane of FIG. 2. This disposition of the guide meansprovides adequate support to resist any tendency of the die parts tobind because of sidewise thrust caused by lateral components of motionof the ram of the press with respect to the bed of the press.

It may be noted that the parts of the die are shown in their closedposition, that is at the bottom of the closing stroke. It may also benoted that a portion of the structure is broken away in FIG. 1 to showthe structure of the die set more clearly; specifically, the forwardguide means 8 is omitted in that figure.

The tubing 14 which is being cut is gripped between two suitablycontoured jaws 15 and 16. Jaw 15 is fixed by machine screws to a firstjaw holder or cross slide 18 which is mounted on the shoe 6 toreciprocate from left to right as viewed in FIG. 1.

The cross slide 18, which rides on a relieved portion of the uppersurface of lower shoe 6, is guided and held down by four gibs 19 (FIGS.1 and 3) received in a slot in the upper surface of the lower shoe andheld in place by machine screws 20. These gibs, which are of L-shapedcross section, enter slots 22 in the sides of the slide 18. A stop plate23 fixed to an end of the shoe 6 limits outward movement of the slide.

The jaw 16 is fixed to the second jaw holder or cross slide 24. Thesecond slide is reciprocable on the upper surface of the slide 18 and isguided by two gibs 26 which enter the slots 22 between the gibs 19. Gibs26 are fixed to the cross slide 24 by machine screws. The jaws 15 and 16are biased apart by two tension springs 27, the ends of which are hookedover posts 29. Each post consists of a sockethead screw 28 and a jam nut30.

The jaws 15 and 16 are closed by a jaw clamping cam 31 which holds thejaws clamped during the greater part of the stroke of the ram. The cam31 is fixed to the upper shoe 7 through a retainer 38. The parts aresuitably fixed together by machine screws. Cam 31 has a thinner leadingportion 32 which allows the springs 27 to open the jaws when the uppershoe is at its upper limit of travel. Cam 31 acts upon the slidesthrough two rollers 34, one mounted on each slide, which follow the camcontours. One roller is mounted on slide 18 by a cross shaft 35 and theother on slide 24 by cross shaft 36. The operation of the clamping meansin the cycle of operation of the cutoff die set should be apparent fromthe foregoing.

The first step in cutting off the tube is to scarf the upper surface;that is, to make a horizontal cut across the top of the tubing whichextends only part way through the tube wall. This is a known expedient.The structure for this comprises a scarfing blade 39 clamped to a holder40 mounted on a carrier or slide 41 reciprocable on an I-section rail 42bolted into a recess in the lower shoe 6. The upper surface of the raillies in a slot in the lower surface of the slide 41, and the slide isheld on the rail by a pair of gibs 43 bolted to the under surface of theslide. The slide 41 is reciprocated on the rail 42 by a dogleg cam 44.Cam 44 depends from upper shoe 7, to which it is bolted. This cam passesthrough a slot in the lower shoe 6 and is backed up by a cam guide 47fixed to one end of shoe 6. Cam 44 drives the slide 41 through tworollers 48, one engaging each edge of the cam. Shafts for these rollersare provided by two bolts 50. A plate 51 held by these bolts bearsagainst the side of cam 44. As the upper die descends from its uppermostposition (not illustrated) to its lowermost position as shown in FIG. 1,the dogleg portion 52 of cam 44 projects the scarfing blade 39 to notchthe tubing and then retracts it so that it is out of the way of theblade 54 which completes the cut. The scarfing blade 39 is adjustablevertically to set it for tubing of different diameters. The holder 40 isadjustably fixed to the slide 41 and its vertical position may be readon a scale 55.

The upper end of the cutoff blade 54 is clamped to a blade holding block56 which in turn is fixed to the upper shoe 7 by machine screws. Theblade passes through opposed slots in the jaws 15 and 16.

The mounting arrangement for the cutoff blade 54 is illustratedparticularly in FIGS. 6 through 10. This provides for mounting the bladein two settings longitudinally of the blade to accommodate two ranges ofdiameters of the tube to be cut off and to reposition a blade shortenedby sharpening.

FIGS. 6 and 7 illustrate a first blade setting. Blade 54 lies in arecess 60 in the face of mounting block 56. A spacer plate 61 isdisposed between the blade and the block. Plates 61 of various thicknessare used with blades 54 of different thickness to locate the centralplane of the blade at a point along the tube aligned with the scarfingblade 39.

The upper end of the blade 54 is driven downward by a backing plate orthrust block 62 which lies between shoe 7 and the end of the blade.Block 62 is fixed to holder 56 by machine screws 63 and both arereceived in a recess 65 in the under surface of shoe 7.

Blade 54 is held against the holder by a clamping plate 66. This plateis held against the blade by three sockethead screws 67 which passthrough three of six holes 69 in the clamping plate and through lateralholes 70 and a lower central hole 71 (FIG. 10) in the blade in thissetting. Screws 67 also pass through holes 73 in the spacer 61 and arereceived in threaded holes 74 in the mounting block 56. Holes 69, 73,and 74 lie in two horizontal rows of three holes each.

To mount blade 54 farther from shoe 7, the screws 67 are taken out andclamping plate 66 is reversed as illustrated in FIG. 9. In thisorientation of plate 66, a flange 75 on the clamping plate extends overthe end of blade 54 and engages block 62 and the blade end to transmitthe driving force to the blade. In this setting, screws 67 pass throughthe three holes 69, 73, 74 in parts 66, 61, and 56 which are not used inthe other orientation of clamping plate 66. They pass through holes 70and through an upper central hole 77 in the blade. Note that thisarrangement of holes in the blade and the overall bolting arrangementavoid use of aligned holes across the blade which would result in a veryconsiderably weaker blade structure.

Thus, with a very simple and easily assembled arrangement, the blade 54is adequately supported and driven in either of two settings relative toshoe 7.

It will be clear to those skilled in the art that the preferred diestructure described herein is highly versatile and advantageous andbenefits from simplicity and economy.

The guiding arrangement between the die shoes, the workpiece clampingstructure, and the blade mounting arrangement all contribute to theadvantages of the assembly.

While the invention has been described with reference to a specificembodiment, it is to be understood that various modifications andadditions to the invention are possible and will occur to those skilledin the art. Accordingly, the foregoing description is not to beconstrued in a limiting sense.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A cutoff die setoperable in various mechanical press arrangements for severing elongateworkpieces comprising, in combination, a lower die shoe, an upper dieshoe, guide post means fixed to the shoes and interconnecting the shoesfor guided relative reciprocation to effect the cutoff, and tube cuttingmeans operated by the relative reciprocation, the guide post meansconsisting of three guide post bushings and three guide posts, each postbeing slidable in one of the bushings; the first and second of the postshaving parallel axes lying spaced apart in a first plane parallel to thedirection of the said reciprocation and the third post and one of thefirst and second posts having parallel axes lying spaced apart in asecond plane parallel to the direction of the said reciprocation andapproximately perpendicular to the said first plane, so that the die setis tolerant of side thrusts of various orientation exerted by a ramoperating the die; the die set including clamping jaw means mounted onone of the shoes for holding a workpiece during the cutoff operation,the clamping jaw means comprising a first carriage slidably mounted onone of the shoes for movement transverse to the direction of relativereciprocation of the shoes and comprising a second carriage slidablymounted on the first carriage for movement opposite to that of the firstcarriage; and means operated by relative reciprocation of the shoes tomove the said carriages.
 2. A cutoff die set operable in variousmechanical press arrangements for severing elongate workpiecescomprising, in combination, a lower die shoe, an upper die shoe, guidepost means fixed to the shoes and interconnecting the shoes for guidedrelative reciprocation to effect the cutoff, and tube cutting meansoperated by the relative reciprocation, the guide post means consistingof guide post bushings and guide posts, each post being slidable in oneof the bushings; the die set including clamping jaw means mounted on oneof the shoes for holding a workpiece during the cutoff operation, theclamping jaw means comprising a first carriage slidably mounted on oneof the shoes for movement transverse to the direction of relativereciprocation of the shoes and comprising a second carriage slidablymounted on the first carriage for movement opposite to that of the firstcarriage; and means operated by relative reciprocation of the shoes tomove the said carriages.
 3. In a cutoff die set including two relativelyreciprocable die shoes, means for holding a workpiece on one die shoe,and a cutoff blade fixed to and driven by the other die shoe, theimprovement in means for attaching the cutoff blade to the die shoecomprising, in combination, a first mount portion having a face abuttingone face of the blade and a shoulder adapted to engage the end of theblade to transmit driving force to the blade; a reversible second mountportion having two faces adapted alternatively to engage the other faceof the blade, and means for clamping the said mount portions togetherwith the blade between them; the second mount portion having a flangeextending from one face thereof adapted to lie between and engage theend of the blade and the shoulder on the first mount portion in oneorientation of the second mount portion to transmit driving force fromthe first mount portion to the blade, the said flange extending awayfrom the blade and the first mount portion in the other orientation ofthe second mount portion to accommodate direct contact between the saidshoulder and the blade end; so that the blade is positively drivinglycoupled to the first mounting portion in either of two degrees ofspacing from the said other die shoe, depending upon the orientation ofthe second mount portion.
 4. In a cutoff die set including tworelatively reciprocable die shoes, means for holding a workpiece on onedie shoe, and a cutoff blade fixed to and driven by the other die shoe,the improvement in means for attaching the cutoff blade to the die shoecomprising, in combination, a first mount portion having a face abuttingone face of the blade and a shoulder adapted to engage the end of theblade to transmit driving force to the blade; a reversible second mountportion having two faces adapted alternatively to engage the other faceof the blade, and means for clamping the said mount portions togetherwith the blade between them; the second mount portion having a flangeextending from one face thereof adapted to lie between and engage theend of the blade and the shoulder on the first mount portion in oneorientation of the second mount portion to transmit driving force fromthe first mount portion to the blade, the said flange extending awayfrom the blade and the first mount portion in the other orientation ofthe second mount portion to accommodate direct contact between the saidshoulder and the blade end; so that the blade is positively drivinglycoupled to the first mounting portion in either of two degrees ofspacing from the said other die shoe, depending upon the orientation ofthe second mount portion; the first and second mount portions having tworows of holes extending transversely to the direction of movement of theblade to receive the clamping means, the clamping means extendingthrough holes in the blade; the holes in the blade comprising an uppercentral hole, two intermediate lateral holes, and a lower central hole.